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Method and apparatus for spiral scan region of interest imaging

  • US 5,805,659 A
  • Filed: 09/30/1996
  • Issued: 09/08/1998
  • Est. Priority Date: 09/30/1996
  • Status: Expired due to Term
First Claim
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1. A scanning and data acquisition method for three-dimensional computerized tomographic imaging of a region of interest of an object which is smaller than the object itself and having upper and lower boundaries which are completely within a field of view of an imaging system and radially centered on a predetermined axis, the method comprising the steps of:

  • applying cone beam energy from a cone beam source to at least a portion of the object;

    defining a source scanning trajectory as a path traversed by the source;

    using the cone beam source and an area detector with at least the source movably positioned relative to the object, for scanning about the region of interest of the object;

    specifying a source scanning trajectory for completely obtaining Radon data for accurately reconstructing a 3D CT image of the region of interest of the object as comprising only a spiral scan defining a plurality of spaced stages on a predetermined geometric surface surrounding the region of interest, such that each plane passing through the region of interest intersects the scanning trajectory in at least one point, the area detector having a predetermined dimension extending sufficiently along a direction generally parallel to the predetermined axis to span at least two consecutive stages having the largest spacing therebetween;

    scanning at a plurality of positions along the source scan trajectory to obtain cone beam projection data corresponding to respective portions of the region of interest; and

    processing the cone beam projection data corresponding to energy which passed through the object, to provide a data set which can be reconstructed into an image of the region of interest of the object.

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